function Lnko(X: in Positive; Y: in Positive) return Positive is
   X: Positive := A;
   Y: Positive := B;
begin
   while A/=B loop
      if A<B then
         B:=B-A;
      else
         A:=A-B;
      end if;
   end loop;
   return A;
end Lnko;

